Silent gear and process of manufacture



ec- 11, 193 w. w. CARTER 1,984,113

SILENT GEAR AND PROCESS OF MANUFACTURE Filed Oct. 7, 1953 Patented Dec. 11, 1934 UNITED STATES PATENT DFFIQE SILENT GEAR AND PRooEss OF MANUFACTURE William Wesley Carter, Cincinnati, Ohio, as-

signor to The Formica Insulation Company, Cincinnati, Ohio, a corporation of Ohio Application October '7, 1933, Serial No. 692,669

11 Claims. (Cl. 154-2) This invention relates particularly to the of fabric which has been impregnated with a manufacture of silent gears and to an improved potentially reactive artificial resin and dried. method of manufacturing th same. This strip is subjected to a series of folds along The primary object is to provide an improved diagonal lines 1 as illustrated in Fig. 1. The

'5 product and an improved method of manufaclines of folding become segments of a circle, and turing the same, which will avoid waste of mathe outer edges 1 of the tape, which intervene terials. Incidentally, the presence of resinbetween the lines of folding, also become segpockets, especially in the rim-portion of the ments of the circle. The inner edges of the gear, is largely avoided. portions of the folded tape are designated 1, and

10 In accordance with the improved process, an it will be noted that these lines are much longer 10 assembly is produced which comprises a wheelthan the outer segmental lines 1 and l It is center composed of binder-impregnated fibrous not essential that the lines 1 be of the same material, and a polygonally-folded binder-imlength as the lines i As the tape, or strip, is pregnated strip which provides a rim-portion; subjected to successive folding operations, the

and the assembly is consolidated under heat and layers accumulate upon each other, in a general '15 pressure. circular form, thus producing a built-up rim- For best results, the binder employed is a assembly which may be placed within the pethermally reactive artificial resin, such as a ripheral flange of the die, or mold, A. potentially-reactive phenolic condensation prod- If desired, impregnated macerated fibrous manot, which will harden and become infusible and terial 2 may be introduced into the mold to fill substantially insoluble when subjected to the acany segmental recesses between the rim-portion tion of heat. The change to the infusible and of the assembly and the flange of the mold. Also, substantially insoluble condition will be effected in Fig. 2, the macerated material supplements wholly in the mold, or partially in the mold and the inner portions of the tape 1.

partially by continued application of heat after, The wheel-center B is shown as comprising 25 removal from the mold. a metal hub 3 and a web 3 of binder-impreg- The invention is illustrated in a preferred emnated macerated material. The web-portion is bodiment in the accompanying drawing, in supplemented by fabric disks 3 one of which whichmay be placed in the mold before the remainder Fig, 1 is a broken plan view illustrating the of the assembly is introduced, and the other of 30 manner in which a binder-impregnated strip is which may be applied just before closing. the polygonally folded (to approximate a ring), it mold; The arrangement in this respect is simibeing understood that the folding of the strip is lar to the illustration given in Fig. 3. continued until several layers have accumulat- In producing the assembly in the mold, macered; Fig. 2 a plan view showing an assembly in ated material may be allowed to fill any spaces a mold, the wheel-center being composed largely intervening between the layers of the polygon-ally of binder-impregnated macerated fibrous mafolded strip 1. terial, the upper layer of fabric which is pref- Assuming a thermally reactive binder to be emerably employed being omitted from this view; ployed in connection with the fibrous material Fig. 3, a broken sectional view illustrating a (whether woven fabric, macerated scrap-fabric, 40 molded assembly in which the wheel-center is or molding-powder containing fibrous material), composed of a spirally wound impregnated tape, the assembly is consolidated under heat and presthe mold being omitted from this view; and sure in a manner well known in the art, and the Fig. 4, a plan view of a quarter-section of a binder is converted to an infusible and substangear blank constructed in accordance with the tially insoluble state. 45 i tio Fig. 4 illustrates a quarter-section of a finished Referring to Figs. 1, 2 and 4, A designates one gear product made in accordance with the invenmember of a mold; and B designates 'a wheel tion. It may be understood to represent the final assembly, prior to the consolidating operation. product produced in accordance with the illustra- The rim-portion of the wheel is designated B tion in Figs. 1 and 2, or by any modification of the 50 and the wheel-center is designated B manner of making the assembly.

The rim-portion preferably comprises a series In Fig. 3, the construction is similar to that al-'- of layers of binder-impregnated tape 1 which is ready described, and the parts are designated,

folded into polygonal form (to approximate a generally, by the same reference characters. In

ring). Preferably, one employs a straight strip this example, however, the wheel-center is shown unnecessary scrap material.

as comprising a metallic hub 4 and a web 4* which is formed by winding impregnated tape upon itself spirally, so that the laminations initially are concentric with the axis of the wheel. In this modification, the rim B may be understood asbeing formed in the manner illustrated in Figs. 1 and 2. Binder-impregnated fabric disks 3 form the side walls of the assembly, the same as in the first-described construction. When the assembly used in Fig. 3 is introduced intoa mold and consolidated under heat and pressure, the effect is to form wrinkles in the layers 4 and bend the lateral edges outwardly, and the outer layers become intermeshed with the inner portions of the layers which form the rim-portion of the assembly. Thus, after the gear blank has been consolidated by heat and pressure, the wheelcenter is strongly bound to the rim. This istrue in both of the constructions described.

It is noteworthy that the manner of forming thesuccessive layers which make up the rim-portion of the gear blank is such as to give great strength to the rim-portion in tangential directions. As noted in Fig. 2, the folding of the strip in producing the layers forming the rim-portion may be done in such manner that the lengths of the segments will mismatch, or bear a staggered relation. This not only tends to produce uniformity of filling, but also to enhance the strength possesses great advantages for gear purposes.

If desired, the hub-portion of the gear-blank .may be formed in a manner analogous to that employed in forming the rim-portion. That is,

a binder-impregnated strip may be folded into polygonal form to provide a hub-portion. This may be supplemented by a central metallic bushing such as the bushing 1 shown in Fig. 3. Where a metallic hub-portion is employed, it is desirable to roughen the circumferential surface in the manner illustrated in Figs. 2 and 3, so that the non-metallic portion of the gear will become firmly interlocked with the metallic portion.

The present invention makes it possible to utilize scrap material and prevent the formation of Thus, a binder-impregnated sheet may be cut into straight strips,

and these strips may be employed for forming rim-assemblies. Scrap material may be macerated and used to supplement the inner margins of the polygonally folded strips in making up the rims, and also such macerated scrap material may be used in forming the webs.

Referring to Fig. 2, the macerated material at 2 may be omitted, and the dies may be depended upon to so compress and compact the fabric layers as to substantially fill all voids at the outer portion of the rim, thus insuring the greatest gear-tooth strength after the gear-cutting opercation.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art.

What I regard as new and desire to secure by Letters Patent is:

1. A process for manufacturing gear blanks comprising: producing an assembly comprising a wheel-center comprising binder-impregnated fibrous material and a rim-portion comprising a a polygonally folded binder-impregnated strip of fabric, the lines of folding being substantially chords of arcs of a circle; and molding the assembly under heat and pressure.

2. A process as set forth in claim 1, in which the assembly includes binder-impregnated fabric disks which form the side walls of the gearblank.

3. In the manufacture of a gear-blank, the step in forming a rim which comprises polygonally folding a strip with the line of folding forming chords of a circle, substantially, and incorporating the strip thus folded in the rim.

l. A process as set forth in claim 3, characterized by impregnating the strip with a solution of an artificial resin and drying it before folding the strip.

5. In the manufacture of a gear-blank, the step which comprises forming a rim-assembly by polygonally folding a binder-impregnated strip of fabric, the lines of folding being substantially chords of arcs of a circle, and continuing the folding of the strip until there have been produced a plurality of superposed layers of polygonal form.

6. The process as set forth in claim 5, characterized by the segments of the layers being out of registration.

'7. A process of manufacturing a gear blank which comprises: introducing into a mold an assembly comprising a plurality of layers of a polygonally folded binder-impregnated strip of fabric, the lines of folding being substantially chords of arcs of a circle, a filling of -binder-im pregnated fibrous material adapted to form .a

web, and fibrous material supplementing the folded strip for forming the rim; and consolidating the assembly under heat and pressure.

3. A gear-blank comprising: a wheel-center comprising a web of binder-impregnated fibrous material; and a rim comprising a polygonally folded binder-impregnated strip of fabric whose lines of folding are substantially chords of arcs of a circle, the whole consolidated under heat and pressure.

9. A gear-blank as specified in claim 8, in,

which the web of the wheel-center comprises disks of woven fabric forming the side walls of the web and binder-impregnated macerated fibrous material between said disks. 

